This invention concerns a laminar block having a plurality of integrally laminated sheet-like members each of which is made of inorganic fibers, a method of producing such a laminar block and a novel apparatus for producing such a laminar block.
Laminar blocks each comprising a plurality of integrally laminated sheet-like members, each of which is made of inorganic fibers are employed, for instance, as linings to the wall part of the main body of a kiln of furnace for use in ceramic industry for heat-insulating or warm-keeping purpose.
One example of conventional laminar blocks used for the lining of the furnace wall is shown in FIG. 1. A laminar block 1 in FIG. 1 comprises blankets 2,2, . . . each of which is made of inorganic fibers. In the laminar block 1 illustrated in the figure, thirteen sheets of rectangular blankets 2 are laminated. A laminer body 4 composed of the thirteen laminated rectangular blankets 2 are integrated to form the block 1 by a single thread 5, which is inserted into the laminar body 4 of the thirteen blankets 2 and bound at the both ends thereof so as to constitute a closed loop 3.
Upon using the laminar block 1 for the lining on the wall portion of the furnace main body, it is disposed and secured within the furnace main body such that a face of the laminar block 1 at which the laminated portion is exposed, or the side face 6 is in contact with the inner surface of the wall portion of the furnace main body.
In the production of the laminar block 1, the size of the block 1 or the size of the blanket 2 is often specified to a certain standard size in view of the productivity or the like. When the laminar block is used for the lining on the wall of furnaces with different sizes or shapes, the laminar block 1 is cut into an optimum shape at the working place of applying the lining corresponding to the shape and the size of the applied portion.
However, in a case where the laminar block 1 illustrated in FIG. 1 is cut, for instance, into two subblocks 8 and 9 along the plane shown by an imaginary line 7 in FIG. 1, the loop 3 of the thread 5 is cut or disconnected at two points 10 and 11 leaving each of the sub-blocks 8 and 9 in a state where the thread part 12 or 13 is merely inserted therein. Accordingly, the laminated blanket portions 2a and 2b of the laminar sub-blocks 8, 9 can no more be kept integral.
For the integral lamination of blankets made of inorganic fibers, it has also been known to apply adhesives between blankets laminated with each other and securing the blankets to each other to form a laminar block.
In the laminer block in which laminated blankets are fixed with each other by means of the adhesives, however, each blanket constituting the laminer block is likely to be separated because each blanket is made of a stack of inorganic fibers.
Moreover, in the case of using inorganic adhesives, for example, in order to provide the laminar block with a sufficient heat-resistance, there is a difficulty in cutting the laminar block due to the high rigidity of the solidified adhesive layer.
Furthermore, in the case where the inorganic adhesives are used between the blankets, there is fear that the adhesives may be firmly sintered with the fibers of the upper and lower blankets upon actual furnace operation, whereby intra-layer peeling may some time be resulted within the blanket in parallel with the plane of adhesion depending on the shrinkage of the fibers.
In addition, upon using the adhesives between the blankets to be laminated, it is actually impossible to move the laminar body until the applied adhesives between the blankets are cured, as well as the intra-layer peeling have often been caused to the blankets when external forces are applied during so-called handling work such as transportation of the laminar block even after the adhesives have been cured.
This invention has been accomplished in view of the foregoings in order to reduce at least a part of the disadvantages of the conventional laminar block and the object thereof is to provide a laminar block which can be cut relatively readily into a desired shape or size as required and in which the laminated state of the cut pieces formed by the cutting of the laminar block is likely to be maintained.
According to this invention, the above object can be attained by a laminar block comprising:
a laminar body composed of a plurality of laminated sheet-like members, each member being made of the inorganic fibers; PA1 at least one first stitching thread parts, each having a first surface thread part extended along an outer surface of a sheet-like member situated at one surface side of the laminar body, a first penetrating thread part extended substantially continuously from one end of the first surface thread part so as to penetrate the laminar body in a direction of a thickness thereof and a second penetrating thread part extended substantially continuously from the other end of the first surface thread part so as to penetrate the laminar body in the direction of the thickness thereof; and PA1 at least one second stitching thread parts, each having a second surface thread part extended along an outer surface of a sheet-like member situated at said one or the other surface side of the laminar body, a third penetrating thread part extended substantially continuously from one end of the second surface thread part so as to penetrate the laminar body in the direction of the thickness thereof, and a fourth penetrating thread part extended substantially continuously from the other end of the second surface thread part so as to penetrate the laminar body in the direction of the thickness thereof at a portion different from that where the first and second penetrating thread parts of adjacent one first stitching thread part penetrate the laminar body. PA1 a sewing needle having a recess capable of engaging and disengaging a thread at a side wall portion on a top end thereof and adapted to be moved reciprocatingly along a longitudinal direction thereof; and PA1 an auxiliary needle adapted to be moved to one outer surface of a laminar body along the sewing needle in a space on one side of the laminar body composed of a plurality of laminated sheet-like members made of inorganic fibers such that a first loop-like thread portion of a sewing thread, engaged upon forward movement of the sewing needle to the recess of the sewing needle when the top end of the sewing needle inserted into the laminar body from the outer surface of a sheet-like member situated on one side thereof is protruded out of the outer surface of a sheet-like member situated on the other side of the laminar body, exposed, upon returning movement of the sewing needle, to said one side of the laminar body passing through the laminar body while being engaged in the recess, and disengaged from the recess of the sewing needle, is engaged with the auxiliary needle upon next forward movement of the sewing needle before the sewing needle is again inserted into the laminar body from said one side, and adapted to be moved apart from said one side of the laminar body in the space on said one side of the laminar body such that the engagement of the auxiliary needle with the first loop-like thread part is released when a second loop-like thread part, engaged to the recess upon the next forward movement of the sewing needle and passed through the laminar body and the first loop-like thread in the state engaged to the recess upon next returning movement of the sewing needle, is exposed to said one side of the laminar body.
In the block according to this invention, if the first stitching thread part is disconnected at the first surface thread part, the integrated state of the cut piece is maintained at least by the second stitching thread part.
In this specification, the laminar body is referred to as a body produced by laminating or stacking a plurality of the sheet-like members made of the inorganic sheet-like members in which laminated or stacked sheet-like members are not integrated with each other, and the laminar block is referred to as the integrated laminar body in which the laminated or stacked sheet-like members are substantially integrated to form a unit.
In an embodiment of this invention, the second surface thread part is situated, for instance, at the outer surface of the sheet-like member situated at the other surface side of the laminar body.
In a preferred embodiment of this invention, a penetrating end of the first penetrating thread part of the first stitching thread part is substantially connected with a penetrating end of the second penetrating thread part on the outer surface of the sheet-like member situated at the other surface side of the laminar body so that the integrated state of the cut pieces can be maintained more firmly or reliably. More preferably, a penetrating end of the third penetrating thread part of the second stitching thread part is substantially connected with a penetrating end of the fourth penetrating thread part on the outer surface of the sheet-like member situated at said one surface side of the laminar body.
Second penetrating thread part of one of the first stitching thread parts and the third penetrating thread part of adjacent one of the second stitching thread parts correspond to one common penetrating thread part that penetrates the laminar body substantially continuously in the direction of thickness thereof at one common portion of the laminar body, and at least one line is included in which a plurality of the first stitching thread parts and a plurality of the second stitching thread parts are arranged alternately.
In a preferred embodiment of this invention, the plurality of the first stitching thread parts and the second stitching thread parts belonging to one line are formed by a continuous thread so that an integrated laminar block can be formed with more ease by stitching.
In a preferred embodiment of this invention, a plurality of lines each of which includes the plurality of the first and the second stitching thread parts formed by the continuous thread are provided so that relatively small cut pieces produced by cutting the laminar block into various shapes may be kept integrated. Each of the plurality of lines may be composed of different threads respectively.
In one preferred embodiment of this invention, the first stitching thread part and the second stitching thread part belonging to at least one line is formed by a single chain stitch of a thread.
In an other preferred embodiment of this invention, the first and the second stitching thread parts belonging to at least one line is formed by a wave-like stitch of one thread (in this specification the "wave-like stitch" is referred to as a kind of stitch explained later in connection with FIG. 5).
In a still other preferred embodiment of this invention, the plurality of the first stitching thread parts and the second stitching thread parts belonging to at least one line comprise two continuous threads crossing to each other to be bound with each other so as to withstand the tensile force, and the first and the second stitching thread parts are formed by the lock stitch of two threads.
At least one of the first stitching thread parts may be adapted to form an independent closed loop from other stitching thread parts, and at least one of the second stitching thread parts may also be adapted to form an independent closed loop from other stitching thread parts. The closed loop may be formed by binding of adjacent thread parts, or by securing of adjacent thread parts by adhesives.
The inorganic fiber constituting the sheet-like member for use in a laminar block according to this invention comprise one or more among a crystallized fiber made of a material such as mullite and alumina, a ceramic fiber made of a material such as alumino silica, a rock wool, a glass fiber, and the like. The fiber may be composed of a plurality of fine twisted fiber. The diameter, the length and the cross sectional shape of the inorganic fiber may optionally be selected depending on the kind of the sheet-like member and application use of the laminar block.
The sheet-like member for use in the laminar block according to this invention may be a blanket, felt and/or bulk fiber assembly.
The density, the thickness, the standard shape or size for each of the sheet-like members, as well as the number of sheet-like materials constituting one laminar block may optionally be selected depending on the application use.
The sewing or stitching thread used in the laminar block according to this invention may be those threads made of natural organic materials such as linen and cotton, those threads made of synthetic organic material such as synthetic rubber, rayon, acetate and nylon, those threads made of synthetic or artificial inorganic fibers such as ceramic fibers, glass fibers and carbon fibers, as well as those threads made of metallic material such as nickel, chromium and stainless steel and a twisted strands made of ceramic fibers or glass fibers, which may be used solely or in admixture of two or more of them so long as the sewing thread can serve to maintain the laminar block or the cut portion thereof in an integrated state until the block or the cut portion thereof is set or disposed to a desired position in an apparatus or the like such as a furnace.
The number of stitches per unit length or the stitch number per inch, that is, the number of the surface thread parts of the first and/or the second stitching thread parts per unit length in each of the lines in the case where there are at least one line comprising a plurality of the first stitching thread parts and the second stitching thread parts, as well as the number of stitches per unit surface area, that is, the number of the surface thread parts of the first and/or the second stitching thread parts per unit surface area of the sheet-like member at a side of the laminar block in the case where there are at least one line comprising a plurality of the first and the second stitching thread parts can optionally be selected depending on the kind and the material of the sheetlike members to be laminated, the density and the thickness of the laminar body or the laminar block, the material and the diameter of the stitching thread, as well as the diameter of the stitching needle that can be used.
Specifically, in the case where the laminar block is properly cut into pieces, for instance, better integrity between each of the laminated sheet-like members in the produced piece or sub-block can be obtained as the number of the stitches is increased. However, if the number of the stitches is excessively increased, the strength of the laminar block may rather be reduced due to the increase of the hole area in the block left after the passing of the sewing needle, and the thread may be slackened due to the joining of adjacent stitches or short-cut of the stitching thread.
Furthermore, since the sheet-like member, e.g., a blanket made of fibers has a considerable hardness due to the nature of the constituent inorganic fibers, a considerable mechanical resistance is resulted upon insertion of a stitching needle and a thread although the blanket is fibrous. Then, the needle and the thread have to be suitably tough and rigid and in a considerable diameter in order to withstand such a mechanical resistance. Thus, it is not so advantageous to increase the number of stitches excessively.
Accordingly, the practical length for each of the stitches (corresponding to the feeding amount or length of the sewing machine), that is, the length for each of the first and/or second surface thread parts is usually in a range between 10-100 mm.
In addition, the length for the surface thread part of the first stitching thread part and that of the second stitching thread part may be equal to or different from each other, or the length of the surface thread part of the first or the second stitching thread part may be or may not be uniform.
The laminar block according to this invention, is applicable not only to the heat-insulating or warm-keeping wall such as the lining of the furnace wall but it is also applicable to other application uses such as sound insulation walls, cold insulation walls and cushions for use at a high temperature.
Another object of this invention is to provide a method of producing the laminar block according to this invention as described above.
In accordance with this invention, the foregoing another object can be attained by a method of producing a laminar block comprising a step of stitching a laminar body composed of a plurality of laminated sheet-like materials, made of inorganic fibers, to each other by at least one thread.
The stitching of the laminar body can be carried out using one thread, two threads or three or more threads. Further, the stitching may be carried out by any means usually employed for the stitching of cloths such as single chain stitch, lock stitch or the like.
In a preferred embodiment of the method according to this invention, the stitching is carried out by the single chain stitch.
The method according to this invention may also comprise a further step of securing adjacent stitching thread parts produced at the stitching step by means of binding or by adhesives so that at least one stitch formed by stitching may form independent closed loop.
A further object of this invention is to provide an apparatus for manufacturing the laminar block according to this invention as described above.
The above object of this invention can be attained in accordance with this invention by an apparatus for a single chain stitch comprising: